Are phospholipase A2 and nitric oxide involved in the alterations in peritoneal transport during CAPD peritonitis?

The Pathophysiology of the Peritoneal Membrane

“…28,29 Vasoactive substances released during the inflammation reaction, particularly NO, play a role in these changes. 30 Indeed, inhibition of NOS with N G -nitro-L-arginine methyl ester improve UF and reverse permeability changes in rat and mouse models of acute peritonitis. 8,31 The three NOS isoforms-neuronal NOS (nNOS, NOS1), inducible NOS (iNOS, NOS2), and eNOS (NOS3)-are differentially expressed in the peritoneal membrane.…”

Peritoneal Membrane Failure in Peritoneal Dialysis Patients

“…Acute peritonitis is associated with increased peritoneal transport rates of low molecular weight solutes and serum proteins [22,23]. This points to an inflammationinduced increase in the effective peritoneal surface area caused by a larger number of perfused microvessels and vasodilation.…”

“…This points to an inflammationinduced increase in the effective peritoneal surface area caused by a larger number of perfused microvessels and vasodilation. This is supported by the higher peritoneal blood flow during peritonitis than after recovery from the infection [23]. In addition a reduced size selectivity is present in the early phase [5], leading to a decrease in the peritoneal restriction coefficient to macromolecules [24].…”

“…Also data on an inhibitory effect of the arginine analogue L-NAME in an experimental model support this mechanism. Studies in CAPD patients have given some indirect evidence of increased NO activity [23,29], but measurement of relevant products of NO synthesis in peritoneal effluent is an insensitive method for the assessment of local NO activity.…”

“…The alterations in peritoneal permeability during peritonitis are also associated by increased concentrations of prostaglandins and cytokines in the effluent [23]. In the acute phase the vasodilating prostaglandins, PGE 2 and 6-keto-PGF 1· were increased 10-fold, while the increase in the vasoconstricting thromboxane B 2 (TxB 2 ) was only 5-fold [24].…”